In three-dimensional ultrasound imaging, or volume imaging, the acquisition of a three-dimensional image is accomplished by conducting many two-dimensional scans that slice through the volume of interest. Hence, a multitude of two-dimensional images is acquired that lie next to another. By proper image processing, a three-dimensional image of the volume of interest can be built out of the multitude of two-dimensional images. The three-dimensional information acquired from the multitude of two-dimensional images is displayed in proper form on a display for the user of the ultrasound system.
Further, in three-dimensional ultrasound imaging, there is often a need to make measurements of anatomical structures within the inspected volume. For convenience to users, a measurement capability is available on three-dimensional ultrasound imaging systems where the user can conduct a measurement directly on the rendered image of the three-dimensional volume containing those anatomic structures. This so called “on-glass” measurement method is very easy and convenient for users. However this technique is susceptible to a so-called “fore-shortening effect”. If the structures being measured are not in the same plane as the plane of the projected image of the three-dimensional volume, the distance measured between the structures as seen on the screen will be less than the true distance between the structures in the actual three-dimensional space.
Therefore, ultrasound systems and methods of performing measurement on three-dimensional ultrasound images have been contemplated. The reference US 2011/0066031 A1 discloses embodiments for providing an ultrasound system for performing a three-dimensional measurement and comprising an ultrasound data acquisition unit configured to transmit ultrasound signals to a target object and receive ultrasound echo signals reflected from the target object to acquire ultrasound data. Further, it comprises a user interface configured to receive input data from a user and a processor configured to form a three-dimensional ultrasound image based on volume data derived from the ultrasound data, establish two or more points on the 3D-ultrasound image based on the input data, generate connection data among the established two or more points on the 3D-ultrasound image, and measure distances among the established two or more points based on the input data and the connection data.
There is a need to further improve such three-dimensional ultrasound systems.